lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Tue, 09 Dec 2014 15:37:53 -0500 (EST)
From:	David Miller <davem@...emloft.net>
To:	asolokha@...kras.ru
Cc:	claudiu.manoil@...escale.com, netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] gianfar: handle map error in gfar_new_rxbdp()

From: Arseny Solokha <asolokha@...kras.ru>
Date: Fri,  5 Dec 2014 17:37:53 +0700

> @@ -2854,7 +2866,15 @@ int gfar_clean_rx_ring(struct gfar_priv_rx_q *rx_queue, int rx_work_limit)
>  		rx_queue->rx_skbuff[rx_queue->skb_currx] = newskb;
>  
>  		/* Setup the new bdp */
> -		gfar_new_rxbdp(rx_queue, bdp, newskb);
> +		rxbdpret = gfar_new_rxbdp(rx_queue, bdp, newskb);
> +		if (unlikely(rxbdpret)) {
> +			/* We drop the frame if we failed to map a new DMA
> +			 * buffer
> +			 */
> +			count_errors(bdp->status, dev);
> +			dev_kfree_skb(newskb);
> +			continue;
> +		}
>  
>  		/* Update to the next pointer */
>  		bdp = next_bd(bdp, base, rx_queue->rx_ring_size);

You need to add much more sophisticated handling of this error.

Otherwise the chip will just stop when it gets to the first
descriptor for which a DMA mapping failed in this way.

What you need to do is allocate and attempt to map the new SKB
_first_, and only if that succeeds will you pass the original
SKB up into the networking stack.

If the DMA mapping fails, you leave the OLD skb in the RX ring
and advance the ring pointer, as if the received packet never
happened.  You are essentially dropping it.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Powered by blists - more mailing lists